This application is based on the benefit of the priority of Japanese Patent Application 2000-250848 filed on Aug. 22, 2000. The entire contents of the application in Japan are quoted here and incorporated in this application.
(1) Field of the Invention
The present invention relates to a temperature measuring method in a pattern drawing apparatus.
(2) Description of the Related Art
Due to high integration and high capacity of LSIs in recent years, the circuit line width required for semiconductor devices is refined more and more.
In these semiconductor devices, conventionally, a desired circuit pattern is prepared by positioning several tens kinds of original drawing patterns (called a reticle or a mask) in the exposure area on a semiconductor wafer with high precision and transfer them. This semiconductor wafer steps and repeats for the optical system, so that the transfer device is called a stepper.
In this semiconductor process, the original drawing pattern forming method uses a substrate with a resist uniformly coated on a glass substrate with Cr deposited on one side thereof, irradiates an electron beam onto the substrate, and scans beam spots according to the pattern design data. The resist on the part with an electron beam irradiated is used as a mask by development, and the lower layer of Cr is etched, and the resist is removed, thus a desired pattern is formed.
When a pattern is to be drawn on a glass substrate like this, if the temperature of the glass substrate is changed during drawing, the glass substrate is expanded or shrunk. During drawing, the glass substrate is fixed on the drawing stage controlled accurately by a laser interference meter and the part of the glass substrate where the pattern is to be drawn is controlled by the measured value of the laser interference meter. Therefore, when the glass substrate is expanded or shrunk during drawing, a pattern position error is caused. For example, the coefficient xcex1 of linear expansion of the glass substrate composed of synthetic quartz is 0.4xc3x9710xe2x88x926, so that when the temperature of the glass substrate is changed by 1xc2x0 C. during drawing, the distance of 130 mm between 2 points on the glass substrate is changed by 130 mmxc3x97xcex1=52 nm and it is a large value as an error of the pattern position. Consequently, when the temperature before the glass substrate is transferred onto the stage is low, the change in temperature during drawing is increased and the error of the pattern position becomes more remarkable.
To avoid the aforementioned problem, temperature-controlled isothermal water is let pass in the neighborhood of the route for transferring the glass substrate so as to stabilize the temperature. For temperature control, it is necessary to install thermometers at the main parts in the substrate transfer route and monitor whether constant temperature is kept.
However, the thermometer always has a certain amount of variation in measured values (absolute value xc2x10.15xc2x0 C. in Class 1 of JIS) for the absolute temperature. Therefore, to set the transfer route at a uniform temperature, it is necessary to calibrate the individual difference of each thermometer. However, to execute temperature calibration, it is necessary to prepare an absolute standard of temperature and adjust all several tens of thermometers, so that adjustment requires much labor.
Further, the thermometers must be installed at locations free of obstruction of transfer of the glass substrate and installed on the stage or in the chamber away from the substrate during drawing, thus a problem arises that it is difficult to measure accurately the temperature of the actual substrate itself.
After all, in a pattern drawing apparatus which cannot measure the temperature accurately like this, it is difficult to form a highly precise pattern on the glass substrate.
The present invention was created in view of the foregoing problem and is intended to provide a temperature measuring method for accurately measuring the substrate temperature during transfer and the substrate temperature during drawing in a pattern drawing apparatus.
To accomplish the above object, the present invention may provide a temperature measuring method in a pattern drawing apparatus having a drawing chamber for drawing a pattern on a substrate to be transferred inside, a stage installed inside the drawing chamber, a standby chamber connected to the drawing chamber, and a thermostatic device installed inside the standby chamber, characterized in that a dummy substrate having a temperature measuring device and a recording device for recording the temperature measured by the temperature measuring device is transferred to the thermostatic device, then transferred into the drawing chamber, and then put on the stage, thus the temperature history of the dummy substrate in the transfer route from the thermostatic device to the stage is measured by the temperature measuring device and recorded in the recording device.
Further, the present invention may provide a temperature measuring method in a pattern drawing apparatus having a drawing chamber for drawing a pattern on a substrate to be transferred inside, a stage installed inside the drawing chamber, a standby chamber connected to the drawing chamber, and a thermostatic device installed inside the standby chamber, characterized in that a dummy substrate having a temperature measuring device and an oscillator for converting and outputting the temperature measured by the temperature measuring device to electromagnetic waves is transferred to the thermostatic device, then transferred into the drawing chamber, and then put on the stage, thus the temperature history of the dummy substrate in the transfer route from the thermostatic device to the stage is measured by the temperature measuring device and the measured temperature is sent from the oscillator and received and detected outside the drawing chamber.
Further, the present invention may provide a temperature measuring method in a pattern drawing apparatus having a drawing chamber for drawing a pattern on a substrate to be transferred inside, a stage installed inside the drawing chamber, a standby chamber connected to the drawing chamber, and a thermostatic device installed inside the standby chamber, characterized in that a dummy substrate having a temperature measuring device and a terminal connected to the temperature measuring device is transferred to the thermostatic device, then transferred into the drawing chamber, and then put on the stage, thus the temperature history of the dummy substrate in the transfer route from the thermostatic device to the stage is measured by the temperature measuring device and detected from the terminal of the dummy substrate via the connection part installed in the transfer route.
Further, the present invention may provide a temperature measuring method in a pattern drawing apparatus having a drawing chamber for drawing a pattern on a substrate to be transferred inside, a stage installed inside the drawing chamber, a standby chamber connected to the drawing chamber, and a thermostatic device installed inside the standby chamber, characterized in that a dummy substrate having a temperature measuring device and a terminal connected to the temperature measuring device is transferred onto the stage, and the connection means installed on the stage and the terminal installed on the dummy substrate are connected, and the temperature of the dummy substrate installed on the stage is detected.
Further, the present invention may provide a temperature measuring method in a pattern drawing apparatus having a drawing chamber for drawing a pattern on a substrate to be transferred inside, a stage installed inside the drawing chamber, a standby chamber connected to the drawing chamber, and a thermostatic device installed inside the standby chamber, comprising a step of transferring a dummy substrate, in a similar shape to that of the substrate, having at least a temperature measuring device for measuring the temperature of a place where it is installed into the thermostatic device, a step of transferring the dummy substrate, transferred into the thermostatic device, into the drawing chamber, and an installation step of transferring the dummy substrate transferred in the drawing chamber and installing it on the stage, characterized in that by a temperature detection device receiving the measured temperature from the temperature measuring device, the temperature history when the dummy substrate passes through the transfer route from the thermostatic device to the stage is detected.
In the embodiment of the present invention, a thermometer is set in a dummy substrate having practically the same shape as that of a mask substrate for forming an original drawing pattern for exposing a semiconductor device pattern, and the dummy substrate is transferred into the drawing chamber under the same condition as that of transferring an actual mask substrate, and the temperature history in the drawing device is measured.
By doing this, a temperature change of an actual mask substrate can be measured, and the temperature control of the drawing device, thermostatic device, and load lock chamber is adjusted as necessary on the basis of the temperature history data of the dummy substrate, or the pattern exposure condition is adjusted, thus a highly precise pattern mask free of misalignment can be manufactured.